What the highly cryptic auto-message is trying to tell you is that the special formatting you are trying to apply to your PM is not allowed. This is a software setting. The standard font size is 2 and if you are trying to make it different or flashing or some snazzy color, you are probably getting this refusal message.
Hope this helps.
You're only given a little spark of madness. You mustn't lose it. (Robin Williams)